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Having done the standard timing belt / water pump replacement with Porken tensioner also installed to replace the original one plus water bridge gaskets replacement, i now have a small coolant leak. Typically there is a couple of teaspoons of coolant on the garage floor after i run the engine for a bit. The pool is probably under where the tensioner sits but there are drops of coolant in a few places under the engine.
As everything is hidden by the belt cover, i can't get to look around for the source of the leak.
Is there somewhere obvious where the leak is likely to be coming from?
Is there a process to follow to investigate this? I am not sure if you can remove the belt covers without removing lots of other parts which might preclude running the engine to force the leak to appear.
I can't see any coolant across the oil pan - you can just about see the teaspoons of coolant on the garage floor and some drops just above this. So it really does look like it is coming from that side of the engine.
Get a pump up cooling system pressure tester that attaches to the reservoir, pump up to around 16 psi and use a boroscope to see under and around things to find the source.
sadly often due to water seeping past the threads of the bolts that hold the water pump on.
gasket sealant on all the bold threads usually fixes it.
cheers
Phil
I had a similar problem recently and a small amount of coolant would "appear" when the motor was warmed up. Try to visualise where the belt tensioner pivot arm sits.
When I saw the leak I figured the likely problem was a pump seal failure but to be able to determine what the problem was one has to remove just about everything needed to be removed prior to demounting the pump. Pressure testing to 10 psig with the coolant still captive will probably tell you whether there is a leak or not and you might be able to see coolant leaking but I doubt it. In my case the pressure dropped slowly but I could not see where it was leaking from. I then decided to drop the coolant and carry out a pneumatic test- i.e. no coolant in the system. The beauty of a pneumatic test is that one can use a soap solution spray to find where the air is leaking from.
To my surprise nothing emanated from the back of the water pump pulley and nothing from the pump to casing joint but almost by accident I discovered air was leaking from the base of the tensioner pivot post. My water pump was 8 years old and has not covered much in the way of mileage. The pivot post bolts into the casing but it is not captive in that when the post is removed it leaves a hole in the casing. The pump came with this post mounted so I would probably never have thought to check the tension or whether it seals. Worse still- the threads are parallel so it is not a naturally sealing joint, there was no sealing washer and no signs of any thread sealant. I suspect the post had loosened a little and hence the leak- how it managed to seal for 8 years is beyond me. Plenty of PTFE tape over the threads and base of the post have solved the problem to date.
Whether or not you have the same issue remains to be seen. Is the pump a recent change out by any chance?
I just posted about my experience with this in another thread!
Short version, I must have poked a small pinhole in radiator during TB job. Looked just like your pic when I spotted the small leak in my garage just after the job.
Hi
My mechanic (who has just replaced/welded the rusty metal on my car just in front of the rear wheels that i needed to pass my MOT) tried various caps from his coolant pressure kit, but none of them fitted. I suspect i will have a problem sourcing such a kit with a cap that fits.
However, having driven the car 5 minutes, you can see the pool of coolant (more than before) and you can see it is dripping from the tensioner bolts.
From this, can you tell where the leak actually is? and how much do i have to remove to sort it out?
That is not the stock Porsche belt tensioner it is a PKT unit. Unfortunately I know very little about those items but hopefully someone lik Ken who invented the thing will chime in and give you his opinion as to what the problem may be and whether there is a simple solution. The PKT does not tap into the water jacket so the problem has to be centred around the water pump.
The potential problem with the stock pivot post leaking that I highlighted earlier may still be appliable in that although the post is deleted and a small Allen bolt is used to seal the threaded hole- it is possible that may be leaking. Other than that there is the water pump gasket and ultimately the water pump seal itself. Unfortuantely I cannot visualise any way to find out what exactly is leaking without removing the main belt cover- hopefully someone may have some more optimistic advice.
What Fred said.
I would suggest that you use Loctite PTFE non setting pipe sealant on all the WP bolt threads,
and the plug for the tensioner pin on the WP body.
As an aside since it appears to be leaking from the tensioner side of the engine,
its also possible the casting of the pump could have a small hole in it.
either way remove the right side top cam cover to see where the leak is.
I removed the belt cover just above the tensioner, and it is clean as a whistle behind there
I undid the suspect bolt on the tensioner bracket and nothing came out.
After more investigation, after i had the engine running and warmed up, i can see movement i.e. drops of coolant in the small diagonal gap that runs parallel to the head gasket. In the picture below (courtesy of Dwayne), this is where the diagonal on the left hand side will fit against the water pump (where there is some lettering).
So i need to try and remove the cam belt covers (i am not sure if this is possible without removing belts, pulleys etc) and get a pressure test to isolate exactly where the leak is emanating from on the water pump.
I partly drained the coolant, temporarily took off the top hose and bottom hose, and took off the distributors off, leads, engine hoist bracket, top left cover, top right cover and eased the middle cover off a bit, and then re-connected the hoses. I then refilled the coolant system, and then applied some pressure via the overflow pipe on the expansion tank.
And i saw nothing. No leaks. I was only able to apply maybe 15 psi pressure - i am guessing the cap was venting above this.
So i put it all back together again, ran the engine up to temperature, and no leaks that i can see.
My provisional conclusion is that it was somehow leaking from the top hose, but in a route i couldn't see or touch.
I am still not sure there is no leak - i need to monitor it over the next week or so to see if it is really sorted.
04-29-2023, 03:46 PM
slight coolant leak
